If you want to enable Europeana to use your image material as part of thematic collections and make it more accessible on the Europeana website, then you need to provide at least a direct link to an image file of at least 0.42 megapixel in size (e.g. ~800*533 pixels). Additionally, the International Image Interoperability Framework (IIIF) is also supported by Europeana and can be used for displaying images on Europeana.
Content Tier 3 (Europeana as a distribution platform for non-commercial reuse)
If you want to make use of Europeana as a distribution platform that enables the use of your image files by private individuals, educators and researchers, then you need to provide at least a direct link to an image file of at least 0.95 megapixel in size (e.g. ~1,200*800 pixels). In addition, you also need to make sure that the text documents come with one of the seven rights statements that allow reuse
4 Creative Commons licences: CC BY-NC, CC BY-ND, CC BY-NC-SA, CC BY-NC-ND;
Content Tier 4 (Europeana as a free reuse platform)
If you want to make use of Europeana as a platform that enables the free reuse of your image files elsewhere then, in addition to the criteria described for Tier 3 above, you also need to make sure that the image file comes with a rights statement that allows free reuse (CC BY, CC BY-SA CC0, or PDM).
Overview of Content tier 2-4 requirements for image files
Thumbnail is available*
An image is available with resolution >= 0.42mpx (~800x533)**